For over 6 years, Huang Wenhua and his team at the Northwest Institute of Nuclear Technology in Xi'an have been working on a potent microwave weapon. This one, which recently won China's National Science and Technology Progress Award, is small enough to fit on a lab work bench, making it theoretically portable enough for land vehicles and aircraft.
Said another way: it's small enough to be convenient, but powerful enough to totally down enemy electronics. A microwave weapon like this could even be fitted to a missile (like the U.S. CHAMP electronic warfare missile) or drone.
Generally, microwave weapons shut down electronic systems (even those with traditional shielding against EMP) by bombarding the target with energy pulses between 300 and 300,000 megahertz. This amount of directed energy interferes with and overloads electronic circuits, causing them to shut down. The higher the energy produced by the system, the greater the disruption (and even physical damage for some very high-powered microwave weapons) of the targeted electronic systems like engines and communications systems.